Lecture 2 pt 2

Question 1

what is the major enzyme involved in transcription

Answer 1

RNA polymerase

Question 2

what is the major enzyme involved in DNA replication

Answer 2

DNA polymerase

Question 3

what direction is RNA synthesized from

Answer 3

5’ to 3’

Question 4

what direction is DNA synthesized from

Answer 4

5’ to 3’

Question 5

true/false RNA is synthesized from an RNA template

Answer 5

• false
• a DNA template

Question 6

RNA polymerase catalyzes the formation of what kind of bond

Answer 6

phosphodiester bond

Question 7

DNA polymerase catalyzes the formation of what kind of bond

Answer 7

phosphodiester bond

Question 8

DNA polymerase catalyzes the formation of what kind of phosphodiester bond from linkage of what

Answer 8

deoxyribonucleotides (dNTPs)

Question 9

RNA polymerase catalyzes the formation of what kind of phosphodiester bond from linkage of what

Answer 9

ribonucleotides (rNTPs)

Question 10

does RNA polymerase require a primer to initiate synthesis

Answer 10

no

Question 11

does DNA polymerase require a primer to initiate synthesis

Answer 11

yes (either DNA or RNA)

Question 12

RNA polymerase has a _____ proofreading mechanism

Answer 12

• modest
• error of 1/10^4

Question 13

DNA polymerase has a _____ proofreading mechanism

Answer 13

• good
• error of 1/10^7

Question 14

why is there a difference in proofreading abilities

Answer 14

• cause DNA is the main copy
• RNA is transient and based off DNA
• if you do RNA wrong, just do it again it doesn’t matter

Question 15

what composes a holoenzyme

Answer 15

the core AND the sigma

Question 16

what does the sigma factor do

Answer 16

enables holoenzyme to bind selectively to diff promotor sequences

Question 17

how many types of core enzymes are there

Answer 17

one type (not one molecule… one type)

Question 18

how many types of σ factors are there

Answer 18

several

Question 19

why are diff σ used by the enzyme

Answer 19

to recognize diff promotors

Question 20

what is a promotor

Answer 20

a region that tells the RNA pol where to sit on the DNA to start transcription

Question 21

describe the transcription cycle of bacterial RNA pol

Answer 21

• initiation starts
• σ factor and core subunit of RNA pol associate to form holoenzyme
• holoenzyme slides along DNA
• σ factor recognizes promotor sequence on DNA
• closed complex forms at promotor
• open complex now forms, aka transcription bubble
• abortive initiation happens, aka scrunching. instead of moving along the DNA, the pol stands there and brings the strand towards itself
• promotor clearance, breaks free from the promotor, and σ is released
• elongation starts
• elongation happens idk thats a later thing
• termination starts
• RNA pol reaches and transcribes termination sequence on template DNA
• a hairpin will form on the RNA
• this causes the RNA pol to release its hold on the RNA

Question 22

what is the yellow part

Answer 22

coding sequence

Question 23

what is the part to the left of the yellow

Answer 23

upstream

Question 24

what is the part to the right of the yellow

Answer 24

downstream

Question 25

what part will be transcribed

Answer 25

Question 26

what is the red part

Answer 26

consensus sequence of the promotor

Question 27

what part will be translated

Answer 27

Question 28

**true/false** initiation of transcription occurs at the ATG start codon

Answer 28

false

Question 29

**true/false** diff promotors are recognized by diff types of sigma factors of RNA polymerase

Answer 29

true

Question 30

what does UTR stand for

Answer 30

untranslated region

Question 31

what are the 2 ends

Answer 31

- amino - carboxyl

Question 32

what decides how much RNA is made

Answer 32

promotor

Question 33

which gene has high and low expression

Answer 33

Question 34

**true/false** promotor sequences are often symmetrical to ease binding options

Answer 34

- **false** - asymmetrical so RNA pol can bind in one orientation only

Question 35

when is the bottom DNA strand the template

Answer 35

if youre going from left to right

Question 36

when is the top DNA strand the template

Answer 36

going from right to left

Question 37

each type of eukaryotic RNA pol contains how many subunits

Answer 37

at least 10

Question 38

what does RNA pol I transcribe

Answer 38

- 5.8S rRNA - 18S rRNA - 28S rRNA

Question 39

what is alpha amanitin

Answer 39

- a compound in a poisonous mushroom - diff RNA pols have diff sensitivity to it

Question 40

what does RNA pol II transcribe

Answer 40

- mRNAs - snoRNA - miRNA - siRNA - lncRNA - *most* snRNA

Question 41

what does RNA pol III transcribe

Answer 41

- tRNA - 5s rRNA - *some* snRNA - *other small* rRNA

Question 42

how sensitive to alpha-amanitin is RNA pol I

Answer 42

insensitive

Question 43

how sensitive to alpha-amanitin is RNA pol II

Answer 43

very sensitive

Question 44

how sensitive to alpha-amanitin is RNA pol III

Answer 44

moderately sensitive

Question 45

how can we use RNA pol sensitivities to alpha-amanitin in lab

Answer 45

you can put a tiny bit of poison (alpha amanitin) into your sample in the lab to determine which RNA polymerase is being used

Question 46

eukaryotic RNA pol require what before they bind selectively to diff promotor sequences

Answer 46

the presence of additional initiation proteins (transcription fators)

Question 47

rank the diff RNA pol sensitivities to alpha-amanitin

Answer 47

- **most** - pol II - pol III - pol I

Question 48

what is often the first transcription factor to bind

Answer 48

TATA binding protein (TBP)

Question 49

the transcriptional start site is usually indicated by what

Answer 49

a +1 arrow

Question 50

what transcription factor has helicase activity

Answer 50

TFIH